The top lawyer for Trump's transition team has ordered the staff to preserve all materials related Robert Mueller's investigation.

The top lawyer for President Trump's transition team has ordered the organization's staff to preserve all records and materials related to the widening investigation by special counsel Robert Mueller into contacts between the campaign and Russian officials.

Michael Caputo, a campaign adviser, was also directed to preserve documents, NBC News reported. Caputo retained as his private counsel Dennis Vacco, the former attorney general of New York state. Vacco didn't respond to questions about the probe.

Donald Trump in the White House

A memo sent Thursday evening obtained by the Associated Press requested the preservation of electronic communications and data, telephone logs, audio recordings, videos, calendars and other items. It also requested the keeping of records related to foreign travel, contacts with Russian "officials, agents or nationals" and background investigations into the top Trump associates now targeted by Mueller's probe.

Former national security adviser Michael Flynn is directed to keep documents relating to the Russia probe. (Carolyn Kaster/AP)

The transition order came the same day that Vice President Mike Pence confirmed that he had hired a private lawyer to represent his interests in the expanding probe. Pence headed the Trump transition until inauguration day.

The transition, a nonprofit structurally separate from the Trump campaign, continues to operate with a small staff.